Short Communication Superior hydrogen production rate by catalytic hydrolysis of ammonia borane using Co-B nanoparticles supported over mesoporous silica particles N. Patel a, ⁎, R. Fernandes a , R. Edla a , P.B. Lihitkar b , D.C. Kothari b , A. Miotello a a Dipartimento di Fisica, Università degli Studi di Trento, I-38123 Povo ( Trento), Italy b Centre for Nanosciences and Nanotechnology and Department of Physics, University of Mumbai, Vidyanagari, Santacruz (E), Mumbai 400 098, India abstract article info Article history: Received 20 January 2012 Received in revised form 22 February 2012 Accepted 29 February 2012 Available online 8 March 2012 Keywords: Ammonia borane Cobalt boride Hydrogen generation Mesoporous silica Nanoparticles Catalyst in the form of Co-B nanoparticles supported on mesoporous silica particles (MSP) was synthesized by chemical impregnation–reduction method. This catalyst powder was used for hydrogen production by hydrolysis of Ammonia Borane (AB) and was compared with Co-B catalyst supported on non-porous silica particles (NSP) and unsupported Co-B powder. It was found that the MSPs synthesized in the present studies have average pore size of about 3.1 nm which were efficient to anchor the Co-B particles with average size of ~ 8 nm on the surface to provide high active surface area and improved degree of dispersion. MSP-supported Co-B catalyst was able to produce expected amount of H 2 gas from hydrolysis of AB with significantly supe- rior generation rate, about 3 times higher than that produced by unsupported and NSP-supported Co-B catalyst. Availability of a large number of under-coordinated Co active atoms owing to the size of nanoparticles, better dispersion, high surface area and good stability against agglomeration during the reaction are the main features acquired by the Co-B nanoparticles supported on MSP that exhibit high catalytic efficiency. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Decreasing fossil fuel reservoir and emission of green house gases are the two strong factors driving the world's attention towards H 2 energy. However, the problems in producing pure H 2 and the lack of safe and efficient H 2 storage system are the major obstacles to be overcome for implementation of hydrogen as an alternative energy carrier [1]. Chemical hydrides such as ammonia borane (NH 3 BH 3 , (AB)) with high gravimetric storage (19.6 wt.%) ability can supply pure hydrogen at room temperature by hydrolysis reaction [2,3]. Several noble metals (Pt, Pd, and Ru) have been used in the past to accelerate the hydrolysis of AB at room temperature [4–6]. But the cost and scarcity of these metals have prevented their commercial utility. Low cost material such as cobalt boride (Co-B) showed excep- tional catalytic performance mainly owing to its unique properties such as isotropic structure, high concentration of coordinative unsatu- rated sites, and its chemical stability [7,8]. In our recent works we have synthesized Co nanoparticles (NPs)-embedded-boron-matrix catalyst thin film using pulsed laser deposition technique, which showed cata- lytic activity similarly to that of Pt and much higher than that of Pd catalyst for the hydrolysis of chemical hydrides (NaBH 4 and NH 3 BH 3 ) [9,10]. In contrast, the Co-B nanoparticles produced in powder form by reduction of cobalt salts mainly agglomerate during field tests due to the exothermic nature of the reaction. The catalytic activity is extremely hampered by the particle agglomeration because of lower surface to volume ratio available after agglomeration. Doping Co-B with promoter metals (Cr, Mo, and W) can efficiently reduce the agglomeration by im- posing atomic barrier between the Co-B NPs [11,12]. Another efficient route to avoid agglomeration is by fixing the metal NPs in the pores of certain supports such as silica, alumina, zeolites, etc. Metal NP catalyst supported on highly ordered mesoporous silica particles (MSP), having pore size of 2–10 nm, has shown outstanding catalytic activity [13,14]. This is mainly due to the high surface area provided by the porous silica support which facilitates the metal NPs dispersion. Cobalt oxide sup- ported on mesoporous silica particles has been found to be particularly convenient for the production of hydrocarbons [15]. However, Co-B supported on MSP has apparently not been studied in the past. Our present work is focused on the synthesis of Co-B particles supported on mesoporous silica particles with high level of dispersion. This supported catalyst was compared with Co-B catalyst supported on non-porous silica particles (NSP) and unsupported Co-B powder for hydrogen production by hydrolysis of Ammonia Borane (AB). 2. Experimental methods 2.1. Catalyst preparation All the chemicals used for the synthesis were acquired from Sigma Aldrich. Non-porous silica particles were prepared by Stober method [16] by hydrolysis and condensation of Tetraethylorthosilicate (TEOS, 99.999%) in ethanol, and in presence of ammonia (NH 3 ) as catalyst. Catalysis Communications 23 (2012) 39–42 ⁎ Corresponding author. E-mail address: patel@science.unitn.it (N. Patel). 1566-7367/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2012.02.030 Contents lists available at SciVerse ScienceDirect Catalysis Communications journal homepage: www.elsevier.com/locate/catcom